Spatially limited filters for the two-dimensional convolution method of reconstruction, and their application to SPECT

Abstract

Because 2D convolution is performed in a finite window area, it is important to seek 2D filters which can produce good reconstruction with small window areas for a reduction in reconstruction time. For this purpose filters defined on finite planes are devised. They are, however, determined so that they better approximate properties primarily imposed on 2D filter functions defined on the infinite plane. Computer experiments and actual SPECT tomograms show that 2D filters of a simple function form produce good results with small convolution windows of 7*7 and 9*9. This will reduce the reconstruction time for the 2D convolution method and hence enhance its practicability.